High-toughness gas shielded arc welding wire for ultra-low heat input automatic welding, and welding method thereof

Abstract

The invention provides a high-toughness gas shielded arc welding wire for automatic welding of ultra-low heat input, and a welding method thereof. The gas shielded arc welding wire comprises the chemical components by mass: 0.04%-0.09% of C, 0.3%-1.0% of Si, 0.5%-1.2% of Mn, less than 0.02% of P, less than 0.01% of S, 0.15%-0.5% of Ti, 0.03%-0.08% of V, 0.02%-0.06% of Nb, 0.9%-1.8% of Ni, 0.3%-0.9% of Cu, and the balance Fe and inevitable purities, and simultaneously meets the requirements of Si / 14+Mn / 27.5+Ti / 24=0.06-0.12; and Ti / 192+V / 51+Nb / 93=(0.5-1.0)C / 12. The high-toughness gas shielded arc welding wire stated in the invention is applicable for automatic welding of ultra-low heat input of no more than 0.25kJ / mm.

Description

technical field [0001] The invention relates to a gas shielded welding wire, in particular to a high-toughness gas shielded welding wire for automatic welding with ultra-low heat input and a welding method thereof, which is suitable for automatic welding with an ultra-low heat input of no more than 0.25kJ / mm. Background technique [0002] Gas-shielded automatic welding with molten electrode has high efficiency, stable and reliable welding quality, easy operation and low overall cost, and has been widely used in various industrial fields. In the construction of long-distance oil and natural gas pipelines, girth welding is a key link in construction, and the advantages of gas metal shielded welding are more obvious, and it has become the mainstream method of pipeline construction welding on site. Since the weld metal belongs to the typical non-equilibrium rapid solidification columnar grain structure, the performance cannot be improved by rolling deformation like the base meta...

AI Technical Summary

Problems solved by technology

However, if the above-mentioned composition system welding wire is applied to the ultra-low heat input gas-shielded welding of no more than 0.25kJ / mm required by the aforementioned overseas pipeline steel pipe users, it will be the same as the commonly used AWS A 5.18ER70S-G gas-shielded solid welding wire. Stripped martensite and M-A components with high carbon and uneven distribution appear in the weld metal, which makes the weld metal severely embrittled, and the impact energy and CTOD fracture toughness drop sharply

Therefore, the current gas-shielded welding wire cannot meet the ultra-low heat input gas-shielded welding requirements of no more than 0.25kJ / mm

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